CSS
.btn{
width: 200px;
height: 50px;
margin:100px auto;
/*background-image: linear-gradient(to left,lightgrey,gold);*/
background-color: hsl(58,100%,50%);
border:5px inset white;
text-align: center;
line-height: 50px;
font-size: 18px;
font-weight: bold;
text-transform: capitalize;
animation:brath 8s linear infinite;
box-shadow: -1px 0px 10px #000;
}
@keyframes brath{
0%{transform: scale(.9);}
25%{transform: scale(1);}
60%{transform: scale(.9);}
100%{transform: scale(1);}
}
